topic forgot root password in Operating System - Linux

forgot root password

juno3 — Sat, 10 May 2003 23:45:38 GMT

If forgot root password , how to get back the password ? thx.

Re: forgot root password

Andy Kruta — Sun, 11 May 2003 01:02:52 GMT

You have to boot into initlevel 1. This will load the system as root, but not load PAM, and thus allow you to change the root password.

Re: forgot root password

Steven E. Protter — Sun, 11 May 2003 01:07:36 GMT

reboot your machine. Any user empowered to shutdown can do it. If nobody other than root can do so, use the power switch. Shut down any and all applications first.

At restart, interupt at the 10 second prompt

type bo
Y to interact with the ipl

hpux -is

After the system boots, passwd

You will be prompted twice.

If you have password protected single user mode then your only other viable option is to let crack run on your passwd file for a few days and hope it guesses it.

SEP

Re: forgot root password

Steven E. Protter — Sun, 11 May 2003 01:15:46 GMT

Disregard my post. I thought I was in HP-UX.

You can run crack on /etc/passwd that will eventually guess the password. Run it on a copy of the passwd file, not the original.

Beware that crack will use a ton of system resources.

SEP

Re: forgot root password

juno3 — Sun, 11 May 2003 02:17:11 GMT

hi Andy ,

I use RH 9 , how to boot to level 1 ? thx.

Re: forgot root password

Vitaly Karasik_1 — Sun, 11 May 2003 07:36:30 GMT

for GRUB boot-loader:

- press "e" when you see boot menu

- go to line with your kernel and press "e" again

- add 1 in the end of the line

- press "b" for boot

Vitaly

Re: forgot root password

juno3 — Sun, 11 May 2003 07:51:19 GMT

Thx VK, after I boot to the system , how can I know what run level it is ? thx.

Re: forgot root password

Vitaly Karasik_1 — Sun, 11 May 2003 08:46:09 GMT

you can check it by

runlevel

commmand.

And if you have command prompt now, you can use

passwd

command in order to set new root password

Re: forgot root password

kenny chia — Mon, 12 May 2003 08:02:00 GMT

Hi
you can try this utility from this web site, assuming you have access to /etc/passwd

http://www.openwall.com/john/

Re: forgot root password

Ralf Puchner — Mon, 12 May 2003 11:20:41 GMT

why not booting Linux from CD or disk (e.g. Installation disk) and mounting the root filesystem from harddisk to /mnt, edit the /etc/passwd and reboot the system.

Voila, most of the linux distributions offers an emergency mode on the installation cd/disk.
And with such a disk it is fairly easy....

Re: forgot root password

Ralf Puchner — Mon, 12 May 2003 11:22:16 GMT

Use

who -r

to get the current runlevel.

Re: forgot root password

Michael Creutz — Mon, 12 May 2003 11:53:17 GMT

1. Reboot the machine, i.e. do followed by

2. As it reboots watch for a message indicating which device is being used as the root device. On a machine I recently did this for it was /dev/hda6

3. Reboot the machine again using an installation disk, either floppy or CD. I use Debian, but the procedure should be similar for other distributions.

4. Proceed only through language selection and configuring the keyboard.

5. Press and activate a shell. Look for a message indicating what editor is available.

6. Mount the root device somewhere, i.e.
mount /dev/hda6 /mnt

7. cd /mnt/etc

8. Edit the file "shadow" (or passwd if not using shadow passwords). Remove the second field from the root line so it starts with "root" followed by two adjacent colons. Leave the rest of the line unchanged. Save the edited file.

9. Remove the installation disk and reboot again. Now root won't need a password.

10. Immediately log in as root and run the passwd command to give root a new password.

Re: forgot root password

Ralf Puchner — Mon, 12 May 2003 12:03:31 GMT

ok that's the conclusion of my posting in detail ;-)